Care and Feeding

General Specifications and Information for Cosworth BD Racing Engines
Built and Maintained by S. Jennings Racing

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Quick Start Reference:

What are you thinking…….

There are NO shortcuts.

  • Oil: 40wt BradPenn Racing Oil or appropriate Joe Gibbs Racing Oil, 80 psi HOT
  • Fuel: 2 psi Fuel Pressure with 7.74 gph /100 hp
  • Fuel: VP C-14 Race Gas or (112 Sunaco Blue Supreme) 112 Min. LEADED RACE gas
  • Coolant: Soft Water 50/50 with Old style Green Antifreeze and Norosion corrosion inhibitor
  • Spark: Check marks for timing belt and ignition.

Care and Feeding Instructions:

We recommend ONLY: 40 wt. BradPenn Racing Oil

Always slightly overfill your oil tank to guaranty maximum oil tank capacity.

Use ONLY Wix Filters.

Warm up is important: Do not exceed peak torque rpm with less than 140 deg f oil temp. Engine life will be shortened. Oil temp is measured in the oil tank.

Most engines are happy with 80 psi. We will advise if your engine has special requirements.

Do NOT deviate from our oil system drawing. This works. 5 copies of requests from hopeful deviants for permission to change the schematic should be sent registered mail to the shop. Include the $500 ( non-refundable) review fee. We will refuse your request.



You just spent $20g or so on your racing engine and you want to save $30 a weekend on your fuel bill?

The correct racing fuel will make your engine last longer and, more importantly, feel better.

#1. Choice : VP C-14
#2. Choice : Sunaco Blue Supreme 112 LEADED Race Gas

Do Not trust the gas at the race track.

If you must have an engine that will run on Track Gas you must send a signed and notarized statement to that effect with the engine when it is sent in for rebuild. The fee for this is only $5 (cash). We will de-tune that engine so that it can run on monkey piss if necessary. Otherwise, we build engines for racing….not for whanking or lazy people.

Use one Holley 12-801 fuel pump or two Bendix Blue Top pumps in parallel with a red Holley regulator set at 2 psi. Your engine needs 7.7 gph at 2 psi per 100 hp to not have an immediate and catastrophic failure.


Lucas Fuel Injected engines normally run 125psi with datum cam set 1 off lean. See Cosworth Data sheet. Oil should be added to fuel for all Lucas fuel injected engines.

Air filters should filter all dirt, rocks and small particles out of the engine air intake. How this is done we don’t really care. Even a small rock can cost you $5,000 to fix.

Rule of thumb is 100 sq inches of filter area for each 100 hp you hope your engine makes. If you have a good air filter……a good air scoop will add as much as 300 rpm on a long straight. If you ever have to run in the rain or on a wet track, block the slurry thrown up off of your tires from being channeled into your air scoop. There is always a bit of sand in the soup. Likewise, if you run on a dirty track, stuff your air scoop with open cell foam saturated with foam air filter oil.

Coolant system:

Corrosion is the biggest problem. Soft water with “Norosion” is the best. Bottled drinking water is second choice. Do not use distilled or de-ionized water unless you use “Original Green” Peak brand antifreeze with silicates ( PKAOB3 ) and Norosion with it. Do NOT use tap water. If your engine is not stored in a heated garage use Peak brand original “Green” antifreeze and “Norosion”. Follow the Norosion directions for prepping the system. They also have a water wetter kind of product if you feel your system needs it. The Norosion people (Jay Ross 847-477-9262) is the only company that we found that could explain why their product works without relying solely on testimonials. The chemical balance is critical.

DO NOT deviate from the recommended cooling system drawing: each detail is important to maximize the efficiency of the available radiator size.

Most of the old limey race cars were tested with down on hp engines in the winter in the UK before shipment and overheat in the US almost by plan. Do Not exceed 100 deg C or 210 deg F water temp as measured as the water comes out of the head. If the engine runs hot, stop and fix it. A fluctuating temperature gauge indicates a low water level. Stop and fix it. If we build a 250 hp engine for your car that was designed for 130 hp your radiators might be too small.

Water pumps for racing engines must have the following:

  1. Inlet from the lowest point on radiator with no spots in line above inlet port on pump.
  2. Fillpot/header tank with ½” id line to “as close to center of impellor as possible” on suction side. Make the tank as big and as high as practical.
  3. Engine outlet with bleed, temperature sensor and restrictor routed directly to top of radiator.
  4. Bleed lines from the engine side of the restrictor and high point or high points on radiator/water pipes must have individual fittings into header tank to function properly. Fittings into header tank must be orientated to allow visual confirmation of flow with engine running.

Exhaust System:

2 litre BDG/X for vintage or 1600 for racing should use:

  1. 2” X 26” ( 30” for broader range) Primary
  2. 4 .5” long 4 into 1 merge collector
  3. 21 ¼ “ long X 2 ½” dia. Tail pipe (30” for broader range)

You can use any muffler as long as it does NOT restrict the flow. Hook up a pressure gauge into the collector and use your data system to verify. OR- watch your tachometer: if there is any loss in RPM , use of the muffler will likely damage your engine.


We currently favor the MSD 6 AL2 digital system.

Champion sparkplugs have been problematic lately so we are exploring NGK. Bernard swears by them.

Champion 57 or 59 or NGK 9 or 10 or Bosch 7 or 8 heat ranges work in just about everything.

Your engine will come timed for the correct polarity. Do not move the distributor without verifying with us that that should be done.

Most of our engines work well at 30 deg adv. Never exceed 33 deg without specific permission from the shop. 30 deg is nearly ¼” of piston drop before TDC.

Use dielectric grease on all low and high voltage wire connections related to the ignition system. This includes spark plug wire ends at the spark and the distributor cap as well as the entire plug in connectors.

Chassis electrical systems (the ground system in particular) are the biggest cause of misfires in racing engines. Do NOT rely on the aluminum panels in a monoque or the tube in a tube frame to act as a reliable ground conductor. Always use a big wire directly to the neg on the battery from the engine block. Connect grounds from everything else to that common point. When the car is wired or, if you have a misfired that won’t go away, run a pair of wires directly from the battery to the ignition system to bypass everything else in the car. If you do this, make sure the driver has a set of side cutters to turn the engine off if he crashes.

General Notes:

Upon receipt of an engine that is new to the car check:

  1. Clearance from the end of the gearbox input shaft to the bottom of the hole in the back of the crank
  2. Bearing or bushing ?
  3. End of spline to aft end of crank and spline engagement in clutch hub.
  4. Clutch release bearing freeplay to clutch fingers

Read all of Carroll Smith’s series "Prepare to …" on the most basic race car preparation.

If I figure out that you did not take my advice and read these instructions, I won’t take you seriously either.

Please advise me if there is anything I missed. I will add it ASAP.

Steve Jennings.